Valve provides a common runtime/build environment for Linux devs in the form of the Steam Linux Runtime. There is version 1 (Scout), which uses an LD_PRELOAD system. There is version 2 (Soldier), which uses cgroups (podman) and is deprecated. Then, there is version 3 (Sniper), which is the current target.
As of right now, proton and proton-ge both build in and require Steam Runtime Version 3 to run in. The steam client itself is running in a runtime, and I think it is the scout runtime, so LD_PRELOAD based. This means that steam has its own common platform to "deploy" against, and all Linux native games have a common platform to deploy against.
It used to be that games had to be compiled in a chroot for Steam runtime 1.0, but now with Steam runtime 3.0, developers are heavily recommended to build their game in a "OCI-based container framework"—so podman basically—and enable the Steam Runtime 3.0 on steam. I know that TF2 and Dota 2 use steam runtime 3.0, and apparently so does Retroarch. Of course, since there is a podman/docker image, you can also test existing games to see if they run in the runtime too.
You can find a lot of more information about the steam runtime 3.0 here: https://gitlab.steamos.cloud/steamrt/sniper/sdk
Valve has a gitlab with lots of great docs for developers who want to publish a linux native game.
I think all native linux games will run in the Scout 1.0 runtime by default
Edit: I will say that as an end-user, running an up-to-date Linux kernel and Mesa stack is important for gaming. I know some people who run Mint and are surprised that their Radeon RX 9060 runs like ass. As long as you aren't using a Debian based LTS distro, like mint or ubuntu lts, or you are running those distro but get a newer kernel, you should be fine. This matters less for older hardware, but having a newer kernel and especially a newer mesa version is important.